I am stuck since 2 days, as I am not to firm with pointers and recursion. I have an array of path like structures, lets say:
s:=[]string {
"a/b/c",
"a/b/g",
"a/d",
}
With a data structure like this:
type Node struct {
Name string `json:"name"`
Children []Node `json:"children"`
}
I would like to end up with something like this:
{
"name": "a",
"children": [
{
"name": "b",
"children": [
{
"name": "c",
"children": []
},
{
"name": "g",
"children": []
}
]
},
{
"name": "d",
"children": []
}
]
}
I tried to build it with a recursion, which works kind of fine, but only for one string (e.g. "a/b/c"), as soon as I try to implement something which should add missing nodes ("g" in "a/b/g") to a tree I am stuck.
I had something like:
func appendChild(root Node, children []string) Node {
if len(children) == 1 {
return Node{children[0], nil}
} else {
t := root
t.Name=children[0]
t.Children = append(t.Children, appendChild(root, children[1:]))
return t
}
}
Could someone point me to an efficient solution?
https://play.golang.org/p/9pER5cwChF
func AddToTree(root []Node, names []string) []Node {
if len(names) > 0 {
var i int
for i = 0; i < len(root); i++ {
if root[i].Name == names[0] { //already in tree
break
}
}
if i == len(root) {
root = append(root, Node{Name: names[0]})
}
root[i].Children = AddToTree(root[i].Children, names[1:])
}
return root
}
Example output (note that I used omitempty on the children field, because I don't like null entries in my JSONs):
[{
"name": "a",
"children": [{
"name": "b",
"children": [{
"name": "c"
}, {
"name": "g"
}]
}, {
"name": "d"
}]
}]
Notable difference from your version:
It operates on a list of nodes instead of the children of a single node. This is important, as your version assumes that all of the trees have the same single root node (a), when this might not be the case. The only way to handle that in your version is to have a "fake" node at the root.
It does NOT reuse the input node. This is one of the primary problems with your code. If len(children) > 1, you update the input node's name, append to it's children, then recurse. This means that every prior level of the slice becomes part of the children. You need to create a new node instead.
It actually searches the tree. You're not searching the tree to see if the item being inserted already exists, so you duplicate nodes (specifically, node b)
Related
I need help with writing my consumer Pacts using pact-jvm (https://github.com/DiUS/pact-jvm).
My problem is I have a field which is a list (an array) of maps. Each map can have elements of different types (strings or sub-maps), eg.
"validatedAnswers": [
{
"type": "typeA",
"answers": {
"favourite_colour": "Blue",
"correspondence_address": {
"line_1": "Main St",
"postcode": "1A 2BC",
"town": "London"
}
}
},
{
"type": "typeB",
"answers": {
"first_name": "Firstname",
"last_name": "Lastname",
}
}
]
but we're only interested in some of those answers.
NOTE: The above is only an example showing the structure of validatedAnswers. Each answers map has dozens of elements.
What we really need is this: https://github.com/pact-foundation/pact-specification/issues/38, but it's planned for v.4. In the meantime we're trying a different approach. What I'm attempting to do now is to specify that each element of the list is a non-empty map. Another approach is to specify that each element of the list is not null. Can any of this be done using Groovy DSL?
This:
new PactBuilder().serviceConsumer('A').hasPactWith('B')
.port(findAvailablePort()).uponReceiving(...)
.willRespondWith(status: 200, headers: ['Content-Type': 'application/json'])
.withBody {
validatedAnswers minLike(1) {
type string()
answers {
}
}
}
doesn't work because it mean answers is expected to be empty ("Expected an empty Map but received Map( [...] )", see also https://github.com/DiUS/pact-jvm/issues/298).
So what I would like to do is something like this:
.withBody {
validatedAnswers minLike(1) {
type string()
answers Matchers.map()
}
}
or:
validatedAnswers minLike(1) {
type string()
answers {
keyLike 'title', notNull()
}
}
or:
validatedAnswers minLike(1) {
type string()
answers notNull()
}
Can it be done?
I would create two separate tests for this, one test for each of the different response shapes and have a provider state for each e.g. given there are type b answers.
This way when you verify on provider side, it will only send those two field types.
The union of the two examples gives a contract that allows both.
You can do it without DSL, sample Groovy script:
class ValidateAnswers {
static main(args) {
/* Array with some samples */
List<Map> answersList = [
[
type: 'typeA',
answers: [
favourite_colour: 'Blue',
correspondence_address: [
line_1: 'Main St',
postcode: '1A 2BC',
town: 'London'
]
]
],
[
type: 'typeB',
answers: [
first_name: 'Firstname',
last_name: "Lastname"
]
],
[
type: 'typeC',
answers: null
],
[
type: 'typeD'
],
[
type: 'typeE',
answers: [:]
]
]
/* Iterating through all elements in list above */
for (answer in answersList) {
/* Print result of checking */
println "$answer.type is ${validAnswer(answer) ? 'valid' : 'not valid'}"
}
}
/**
* Method to recursive iterate through Map's.
* return true only if value is not an empty Map and it key is 'answer'.
*/
static Boolean validAnswer(Map map, Boolean result = false) {
map.each { key, value ->
if (key == 'answers') {
result = value instanceof Map && value.size() > 0
} else if (value instanceof Map) {
validAnswer(value as Map, false)
}
}
return result
}
}
Output is:
typeA is valid
typeB is valid
typeC is not valid
typeD is not valid
typeE is not valid
This question already has answers here:
How to deep copy a map and then clear the original?
(6 answers)
Closed 4 years ago.
What am I trying to do?
Copy a "default" struct into a new one when needed, keeping all it's values.
Details
I am trying to copy a Chat struct:
type ChatData struct {
User map[string]map[string]string `json:"user"`
Chat map[string]string `json:"chat"`
}
type Chat struct {
Settings map[string]map[string]interface{} `json:"settings"`
Data ChatData `json:"data"`
}
I only need to do this when a new chat is introduced, and I check for membership in a map[string]Chat.
//data is a map[string]Chat
if _, exists := data[event.Chat]; !exists {
data[event.Chat] = data["default"]
}
The full default struct is:
{
"default": {
"settings": {
"eightball": {
"messages": [
"yes",
"no",
"maybe"
]
},
"main": {
"blacklistedCommands": [],
"blacklistedUsers": [],
"error": "there was an error - ",
"maxConsecutive": 5,
"permissions": "You don't have permissions for that command.",
"success": "The command was successful.",
"whitelistedCommands": [],
"whitelistedUsers": []
}
},
"data": {
"user": {
"default": {
"admin": "false",
"consecutiveCommands": "0",
"nickname": "",
"sentMessages": "0"
},
"total": {
"admin": "false",
"consecutiveCommands": "0",
"nickname": "",
"sentMessages": "0"
}
},
"chat": {
"commandSender": "",
"lastMessage": "",
"lastSender": "",
"lastTimestamp": "",
"wasCommand":""
}
}
}
}
What have I tried
data[event.Chat] = data["default"]
// causes a reference
data[event.Chat] = &data["default"]
// cannot use &data["default"] (type *Chat) as type Chat in assignment
data[event.Chat] = *data["default"]
// invalid indirect of data["default"] (type Chat)
Do I need to change my use of map[string]Chat to map[string]*Chat and go with the second option? Pointers and references are not my specialty, so help would be appreciated.
Edit
whoever thought I was copying a map, what are you smoking?
I have found in previous cases, that an easy (though not the most efficient) way to copy a complex structure is to Marshal it, and then Unmarshal it into a new variable. This can be done with a variety of encodings. Two easy ones (included in the stdlib) would be json and gob.
There are also plenty of libraries using reflection to achieve a similar goal: https://github.com/jinzhu/copier
But like I said, though not as efficient, this is easy to reason about and takes just a single, simple function to achieve. If performance matters you should prefer gob over json. If performance REALLY matters, then you should prefer another solution altogether.
If you know the data structure it is best for you to fully define your structs. It will be much easier to manage than complex maps and interfaces with reflection to cast data types. Here is a tool to help you convert JSON to Go structs. It isn't perfect and you have to confirm the data types. You may even want to rip out the internal structs and create types for them for readability and maintenance, but it will save you some time.
https://mholt.github.io/json-to-go/
package main
import (
"encoding/json"
"fmt"
"log"
)
var rawDataExample = []byte(`{
"default": {
"settings": {
"eightball": {
"messages": [
"yes",
"no",
"maybe"
]
},
"main": {
"blacklistedCommands": [],
"blacklistedUsers": [],
"error": "there was an error - ",
"maxConsecutive": 5,
"permissions": "You don't have permissions for that command.",
"success": "The command was successful.",
"whitelistedCommands": [],
"whitelistedUsers": []
}
},
"data": {
"user": {
"default": {
"admin": "false",
"consecutiveCommands": "0",
"nickname": "",
"sentMessages": "0"
},
"total": {
"admin": "false",
"consecutiveCommands": "0",
"nickname": "",
"sentMessages": "0"
}
},
"chat": {
"commandSender": "",
"lastMessage": "",
"lastSender": "",
"lastTimestamp": "",
"wasCommand":""
}
}
}
}
`)
type Settings struct {
Default struct {
Settings struct {
Eightball struct {
Messages []string `json:"messages"`
} `json:"eightball"`
Main struct {
BlacklistedCommands []string `json:"blacklistedCommands"`
BlacklistedUsers []string `json:"blacklistedUsers"`
Error string `json:"error"`
MaxConsecutive int `json:"maxConsecutive"`
Permissions string `json:"permissions"`
Success string `json:"success"`
WhitelistedCommands []string `json:"whitelistedCommands"`
WhitelistedUsers []string `json:"whitelistedUsers"`
} `json:"main"`
} `json:"settings"`
Data struct {
User struct {
Default struct {
Admin string `json:"admin"`
ConsecutiveCommands string `json:"consecutiveCommands"`
Nickname string `json:"nickname"`
SentMessages string `json:"sentMessages"`
} `json:"default"`
Total struct {
Admin string `json:"admin"`
ConsecutiveCommands string `json:"consecutiveCommands"`
Nickname string `json:"nickname"`
SentMessages string `json:"sentMessages"`
} `json:"total"`
} `json:"user"`
Chat struct {
CommandSender string `json:"commandSender"`
LastMessage string `json:"lastMessage"`
LastSender string `json:"lastSender"`
LastTimestamp string `json:"lastTimestamp"`
WasCommand string `json:"wasCommand"`
} `json:"chat"`
} `json:"data"`
} `json:"default"`
}
type Data struct {
Events map[string]Settings
}
func main() {
var settings Settings
err := json.Unmarshal(rawDataExample, &settings)
if err != nil {
log.Fatal(err)
}
event := "foo"
d := Data{
Events: make(map[string]Settings),
}
if _, ok := d.Events[event]; !ok {
// event doesn't exist
// add it
d.Events[event] = settings
fmt.Println("event added")
}
if _, ok := d.Events[event]; !ok {
// event exist, this will never be happen
// sanity check
fmt.Println("this will never be printed")
}
fmt.Printf("%+v\n", d)
}
Super simple fix, just wanted to get some input before I did it. Changed the map[string]Chat > map[string]*Chat and made a new *Chat, then copied the data.
data[event.Chat] = &Chat{}
*data[event.Chat] = *data["default"]
I want to have definitions section better generated and organized and for me this would mean to not allow depth building up in definitions, but, each class involved in the structure tree should have its own entry in the definitions section and referenced via $ref. This means that for each definition I would only have a list of properties that would either be of primitive types (string, boolean, etc.) or would be a $ref to another definition entry for another custom class. You can also see this as depth 1 definition, close to how classes are originally defined in C#.
To illustrate this via a trivial example:
JSchemaGenerator schemaGenerator = new JSchemaGenerator();
schemaGenerator = new JSchemaGenerator()
{
DefaultRequired = Newtonsoft.Json.Required.DisallowNull,
SchemaIdGenerationHandling = SchemaIdGenerationHandling.TypeName,
SchemaLocationHandling = SchemaLocationHandling.Definitions,
SchemaReferenceHandling = SchemaReferenceHandling.Objects,
};
JSchema schema = schemaGenerator.Generate(typeof(Setting));
Renders:
{
"id": "Setting",
"definitions": {
"SubSetting": {
"id": "SubSetting",
"type": "object",
"properties": {
"SubSubSetting": {
"id": "SubSubSetting",
"type": "object",
"properties": {
"String": {
"type": "string"
}
}
}
}
},
"SubSubSetting": {
"$ref": "SubSubSetting"
}
},
"type": "object",
"properties": {
"SubSetting": {
"$ref": "SubSetting"
},
"SubSubSetting": {
"$ref": "SubSubSetting"
}
}
}
Thus, SubSubSetting definition is placed inline SubSetting definition and later we have SubSubSetting defined as reference to that inline definition. That's what I want to avoid as for complex data structures it becomes really obscure and I want to provide the schema even as part of a living, auto-generated documentation based on data annotations and JsonProperty.
How can I accomplish this using JSchemaGenerator?
Maybe I shouldn't do this, but as a second very short question: Are those $ref syntactically correct? Shouldn't they look like "#/definitions/SubSetting"?
The latest version of Json.NET Schema (3.0.3) has been updated to fix this issue. SubSubSetting will contain the full definition and not just a $ref.
https://github.com/JamesNK/Newtonsoft.Json.Schema/releases/tag/3.0.3
We have the following legacy data structure of Parent and Child objects of the same type
Parent1(name1,code1,null)
Child11(name11,code11,Parent1)
Child12(name12,code12,Parent1)
Parent2(name2,code2,null)
Child21(name21,code21,Parent2)
Child22(name22,code22,Parent2)
etc.
We have a legacy service available that returns a Set of all the Child objects. The Parent objects are not returned but we can call a getParent() getter for a particular Child in the Set to get its Parent. We need to call this service from a Groovy class, and afterwards build a Map that reflects the original structure
def dataMap = [data:[["name":"name1", "code":"code1",
"children":[["name":"name11", "code":"code11"],
["name":"name12", "code":"code12"]]],
["name":"name2", "code":"code2",
"children":[["name":"name21", "code":"code21"],
["name":"name22", "code":"code22"]]]]]
So basically the Map keys are the Parent (name,code) pairs, and the values are Lists of the respective Child objects' (name,code) pairs (the Map will be rendered to JSON afterwards actually)
Being quite novice to Groovy I could probably solve this using Java syntax, but I wonder whether there is a more concise solution using Groovy specific features? Any ideas are appreciated
So as I understand it, this is the setup you have:
import groovy.transform.*
import groovy.json.*
#TupleConstructor(includeFields=true)
class Node {
String name
String code
private Node parent
String getParentName() { parent?.name }
String getParentCode() { parent?.code }
}
def parent1 = new Node( 'name1', 'code1', null )
def child11 = new Node( 'name11', 'code11', parent1 )
def child12 = new Node( 'name12', 'code12', parent1 )
def parent2 = new Node( 'name2', 'code2', null )
def child21 = new Node( 'name21', 'code21', parent2 )
def child22 = new Node( 'name22', 'code22', parent2 )
// This is returned by a call to your API
Set nodes = [ child11, child12, child21, child22 ]
Then, you can do the following (there are probably other routes, and this will only work for single depth trees)
// Get a set of parent nodes
Set parents = nodes.collect { [ name:it.parentName, code:it.parentCode ] }
// Utility closure to return a name and code in a Map
def format = { Node n ->
[ name: n.name, code: n.code ]
}
// Collect the formatted parents with their formatted children into a Map
def dataMap = [ data:parents.collect { p ->
p + [ children:nodes.findAll {
it.parentName == p.name && it.parentCode == p.code
}.collect { format( it ) } ]
} ]
// Print the JSON representation of this
println new JsonBuilder( dataMap ).toPrettyString()
That should print:
{
"data": [
{
"name": "name2",
"code": "code2",
"children": [
{
"name": "name21",
"code": "code21"
},
{
"name": "name22",
"code": "code22"
}
]
},
{
"name": "name1",
"code": "code1",
"children": [
{
"name": "name11",
"code": "code11"
},
{
"name": "name12",
"code": "code12"
}
]
}
]
}
Is there a one liner or how can I get all instances of a named list in any node?
say I get jason where multiple nodes could have a sub collection called "comments". How can I get all nodes that contain a collection of "comments"?
Thanks,
If you can provide an example of the JSON, I can give you a definitive answer.
However, I can post some of the JSON I'm parsing and you can see how it works and possibly shape it to fit your needs.
"abridged_cast": [
{
"name": "Clark Gable",
"characters": ["Rhett Butler"]
},
{
"name": "Vivien Leigh",
"characters": ["Scarlett O'Hara"]
},
{
"name": "Leslie Howard",
"characters": ["Ashley Wilkes"]
},
{
"name": "Olivia de Havilland",
"characters": ["Melanie Hamilton"]
},
{
"name": "Hattie McDaniel",
"characters": ["Mammy"]
}
],
Notice how abridged_cast is an array of values, and one value in that array (characters) is an array itself.
Here's how I fetch the data:
var castMembers = (JArray) x["abridged_cast"];
foreach (var castMember in castMembers)
{
CastMember member = new CastMember();
member.Actor = (string) castMember["name"];
var characters = (JArray) castMember["characters"];
foreach (var character in characters)
{
member.Characters.Add((string)character);
movie.Cast.Add(member);
}
}